The invention relates to a variator for an infinitely variable toroidal drive or transmission particularly of a motor vehicle including a support trunnion, a roller rotatably supported on the support trunnion and lubricant supply means for lubricating the various variator components
In the variators for infinitely variable toroidal transmissions, particular attention is given to lubricating and/or cooling the mechanically stressed components. These components are, in particular, bearings (radial or axial bearings) which are indirectly or directly connected between a support trunnion, an eccentric shaft and/or a roller. There is a further need for lubrication and/or cooling in the region of the traction force-transmitting contacts between the roller and a toroidal disks.
From the publication U.S. Pat. No. 6,238,318, it is known to provide the support trunnion with bores, the outlet of which is arranged in the region of a lubrication point to be cooled and/or lubricated. Since the ambient pressure prevails in the region of the lubrication point, the lubrication point is supplied essentially at zero pressure. However, an exact optimum setting of the volume of lubricant and the pressure of the lubricant is not possible, so that an undefined distribution of lubricant to one or more lubrication points occurs. In particular, an unnecessarily high amount of lubricant may be delivered in the region of an axial needle bearing which serves to support an eccentric shaft with respect to the support trunnion in the direction of the axis of rotation of the roller.
The publication EP 1 143 167 discloses a solution, in which an eccentric shaft has a bore which is oriented in the longitudinal direction and is connected for lubricant purposes to radial bores which emerge from the eccentric shaft in the region of a radial needle bearing arranged between eccentric shaft and roller and of an axial ball bearing. Further bores are connected downstream of the radial needle bearing in the direction of the flow of lubricant and serve to lubricate the engagement surfaces between roller and toroidal disks. However, this lubrication is possible only if the radial needle bearing connected upstream in the direction of flow is supplied with lubricant to a sufficient extent.
The publication U.S. Pat. No. 6,616,568 discloses a pressurized lubricant supply wherein a sealed axial needle bearing is arranged between the support trunnion and the eccentric shaft. Problems arise with regard to the tightness, in particular if the components involved sag or deform elastically as a consequence of the mechanical stresses to which they are subjected. Furthermore, bores are provided which are arranged adjacent to the engagement or running surfaces of the roller and the diameters of which are reduced in comparison with further supply lines, which are connected thereto for lubrication purposes, and via which lubricant is applied to the engagement surfaces of the roller.
Further prior art is known, for example, from the publications U.S. Pat. No. 4,453,427, JP 2001 263442 A and EP 1 316 743 A2. The latter discloses rollers which have outlet channels with a narrowing cross-sectional width.
It is the object of the present invention to provide a variator which permits a simplified and/or improved lubrication and/or cooling of the mechanically stressed components of an infinitely variable toroidal transmission.